An elastoplastic damage constitutive model is constructed in this work to describe the macroscopic mechanical behaviors of geomaterials with a “porous matrix - inclusion” microstructure. In order to consider the influences of microstructure on its nonlinear behavior, such as the porosity, volume fraction of inclusions and the properties of the solid phase, the macroscopic yield criterion derived in Shen et al. (2013) is adopted. By introducing a general damage factor, this criterion is extended phenomenologically to describe the elastoplastic damage behavior of the studied geomaterial. A plastic hardening law of the solid phase is considered to capture the hardening behavior. Then, a complete constitutive model is constructed by using a fractional plastic flow rule to calculate the macroscopic plastic deformation. The degree of non-associativity of the plastic flow rule can be controlled by the fractional derivative of the yield function, which avoids the introduction of macroscopic phenomenological plastic potential. The proposed model is implemented and applied to describe the mechanical behavior of claystone. Comparisons between the numerical predictions and experimental data show that the proposed model is able to capture the main mechanical features of the studied geomaterial, such as the damage procedure, the transition from volumetric contractancy to dilatancy and the brittle to ductile transition with the increase of confining pressure.

本文构建了弹塑性损伤本构模型来描述具有“多孔基体-夹杂物”微观结构的土工材料的宏观力学行为。为了考虑微观结构对其非线性行为的影响，如孔隙率、夹杂物的体积分数和固相性质，Shen等人推导了宏观屈服准则。(2013) 被采纳。通过引入一般损伤因子，该准则在现象学上被扩展以描述所研究的地质材料的弹塑性损伤行为。固相的塑性硬化规律被认为可以捕捉硬化行为。然后，利用分数塑性流动法则构建完整的本构模型，计算宏观塑性变形。塑性流动规律的非结合程度可以通过屈服函数的分数导数来控制，避免了宏观唯象塑性势的引入。所提出的模型被实施并应用于描述粘土岩的力学行为。数值预测与实验数据的比较表明，所提出的模型能够捕捉到所研究岩土材料的主要力学特征，如损伤过程、体积收缩向剪胀的转变以及随着围压增加而从脆性转变为延性的转变。压力。